P2528
Vacuum Reservoir Pressure Sensor Circuit High
Vacuum / actuator control
Generic OBD-II
Low
What it means
P2528 means the vacuum reservoir pressure sensor circuit is reading a higher voltage than expected. This sensor tells the computer how much vacuum is stored for vacuum-operated devices, so the fault is usually in the sensor, its wiring, or the reservoir plumbing rather than the engine. It typically affects vacuum-driven systems, not how the engine runs.
Low
Can I keep driving? Generally drivable. The engine runs, but vacuum-operated systems (such as certain emissions actuators or brake-assist reservoirs) may not work as intended.
Common symptoms
What you'll notice
- Check-engine light on
- Vacuum-driven actuators slow or unresponsive
- Possible reduced brake-booster assist on vehicles that use this reservoir
- No change in starting; engine runs normally
Common causes
Most likely first
- Vacuum reservoir pressure sensor signal wire shorted high or openLikely
- Faulty vacuum reservoir pressure sensorCommon
- Corroded or loose sensor connectorCommon
- Open reference or ground raising the sensed voltageLess often
- Leak or blockage in the vacuum reservoir plumbing skewing readingsLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check the sensor's live value against actual reservoir vacuum.
- Inspect the sensor connector and wiring for corrosion, an open, or a short to voltage.
- Confirm the 5-volt reference and ground are present at the sensor.
- Check the reservoir and its vacuum lines for leaks or blockage.
- Replace the sensor if wiring and vacuum supply are good, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2528?+
Usually yes, but if your vehicle uses this reservoir for brake assist, watch for a harder brake pedal and get it checked promptly.
Can I just clear P2528?+
It returns until the sensor or its circuit is repaired. Trace the high-reading fault first.
Related codes
Often seen with P2528
Read & clear P2528 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX